Microwave-Assisted Heck Arylations of Non-ActivatedN-Acyl-3-pyrrolines with Arenediazonium Tetrafluoroborates
摘要:
Successful Heck-Matsuda arylations of non-activated olefins applying microwave irradiation as an alternative heating mode are presented. Cleaner reactions were performed with arenediazonium tetrafluoroborates bearing electron-donating and electron-withdrawing groups in good to excellent yields with reaction times reduced from 3.5-18 h to 12-30 min.
Heck arylations of N -acyl-3-pyrroline and N -acyl-1,2,5,6-tetrahydropyridine with aryldiazonium salts. Short syntheses of aryl γ- and δ-lactams, baclofen, homobaclofen and analogues
摘要:
Heck arylation of N-acyl-3-pyrrolines and an N-acyl-tetrahydropyridine with aryldiazonium tetrafluoroborates under phosphine-free conditions proceeded smoothly to give alpha-hydroxycarbamates (hemiaminals) or alpha-alkoxycarbamates which were oxidized to the desired gamma- and delta-lactams. Acidic hydrolysis of the gamma-lactams produced a series of arylated GABA derivatives, including baclofen, a useful therapeutic drug. in only three steps with ail overall yield of 63 76%, Starting from N-acyl-tetrahydropyridine, aryl-delta-lactams and higher homologues of baclofen can be obtained. (C) 2002 Elsevier Science Ltd. All rights reserved.